With the advent of computer networking, such as local-area networks (LAN), wide-area networks (WAN), intranets and the Internet, several applications have become popularized. In one such application, a user of a first client computer is able to “call” and communicate with a user of a second client computer. This type of application is generally known as computer telephony.
To accommodate computer telephony, operating systems such as versions of the MICROSOFT WINDOWS operating systems include telephony application programming interfaces, or TAPI's. (It is noted that TAPI typically refers specifically to Microsoft's Telephony API and is not usually used in reference to other telephony API's. However, as used in this application, TAPI refers to telephony API's generically.) Application programming interfaces (API's) are interfaces by which computer programs can provide for specific functionality that is included within the operating systems. This means that programmers developing such programs do not have to develop their own code to provide this functionality, but rather can rely on the code within the operating system itself. Thus, a TAPI relates to a computer telephony application programming interface.
In the MICROSOFT WINDOWS 95 operating system, as well as other versions of the MICROSOFT WINDOWS operating system, TAPI version 2.1 provides for some basic computer telephony functionality for utilization by computer programs. In particular, TAPI 2.1 provides for call control—the initiation and termination of computer telephony calls. However, call control is only one aspect of computer telephony. For example, once a computer telephony call is placed, the media aspects of the call must also be controlled. However, TAPI 2.1, as well as other prior art telephony API's, do not provide for this functionality.
The media aspects of the call relate to the information (or, media) that is itself the subject of the call. For example, a voice call includes audio information transmitted by both the caller and callee of a call, a video call includes both audio information and visual (video) information, etc. Currently, any multimedia devices that are to be used in conjunction with a computer telephony call—such as microphones to detect sound, and speakers to play sound—must have specific drivers written for this purpose, to be used specifically in conjunction with computer telephony calls. Other multimedia devices that may be present, in other words, may not be usable in conjunction with the call.
TAPI 2.1, as well as other prior art telephony API's, are also represented as a framework that is not easily expanded. For example, TAPI 2.1 is procedurally based, which means the API cannot easily accommodate new aspects and features without redeveloping the entire API. For the reasons outlined in this background, as well as other reasons, there is, therefore, a need for the present invention.